Horton

Re: COPY FROM WHEN condition

Corey Huinker <corey.huinker@gmail.com>

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From: Corey Huinker <corey.huinker@gmail.com>
To: surafel3000@gmail.com
Cc: cmt@burggraben.net, pgsql-hackers@lists.postgresql.org
Date: 2018-10-11T09:12:48Z
Lists: pgsql-hackers 
On Thu, Oct 11, 2018 at 5:04 AM Surafel Temesgen <surafel3000@gmail.com>
wrote:

>
>
> On Thu, Oct 11, 2018 at 12:00 PM Christoph Moench-Tegeder <
> cmt@burggraben.net> wrote:
>
>> You can:
>>   COPY ( query ) TO 'filename';
>>
> it is for COPY FROM
>
> regards
> Surafel
>

It didn't get far, but you may want to take a look at a rejected patch for
copy_srf() (set returning function)
https://www.postgresql.org/message-id/CADkLM%3DdoeiWQX4AGtDNG4PsWfSXz3ai7kY%3DPZm3sUhsUeev9Bg%40mail.gmail.com
https://commitfest.postgresql.org/12/869/

Having a set returning function gives you the full expressiveness of SQL,
at the cost of an extra materialization step.

Commits

  1. Remove unused struct member, enforce multi_insert callback presence.

  2. Separate per-batch and per-tuple memory contexts in COPY

  3. Fix handling of volatile expressions in COPY FROM ... WHERE

  4. Allow COPY FROM to filter data using WHERE conditions

  5. Remove obsolete netbsd dynloader code